RESUMO
The Spodoptera complex of the family Noctuidae, represented here by S. frugiperda (J.E. Smith), S. eridania (Stoll), S. albula (Walker), and S. cosmioides (Walker), is an important group of crop pests in Brazil. Spodoptera frugiperda and S. eridania are invasive in Africa, and the former also in Asia and Oceania. The egg parasitoids Telenomus remus Nixon (Hymenoptera: Scelionidae) and Trichogramma spp. (Hymenoptera: Trichogrammatidae) are potential control agents for field use against these noctuids. We evaluated the parasitism efficiency, development, and flight capacity of an isofemale line and a regular line of T. remus, and 2 genetically variable populations of Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman and Platner (Hymenoptera: Trichogrammatidae) in these 4 members of the Spodoptera complex. All parasitoids were able to develop in the 4 hosts. The parasitoids showed good flight capacity, except for the regular line of T. remus. The Trichogramma species, despite having high viability and female:male sex ratios, showed poorer parasitism performances than T. remus. The regular T. remus line also showed good parasitism capacity and high viability but had a predominance of males. In general, the isofemale line of T. remus showed good rates of parasitism and flight capacity as well as a high viability and sex ratio, proving to be a potential candidate for an augmentative biological-control program for Spodoptera spp Guenée (Lepidoptera: Noctuidae).
Assuntos
Besouros , Himenópteros , Feminino , Masculino , Animais , Spodoptera , Óvulo , Brasil , BiologiaRESUMO
The widely distributed, polyphagous fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797), is one of the most important crop pests worldwide. The egg-parasitoid wasp, Telenomus remus Nixon, 1937, is frequently described as a possible control agent for S. frugiperda. We selected an isoline of T. remus and evaluated its parasitism potential (for 24 h) in S. frugiperda eggs, in laboratory conditions, and also its ability to fly at different temperatures and relative humidity levels, aiming to provide basic information about this isoline. The selected isoline maintained good flight capacity without affecting its parasitism efficiency or developing inefficient haplotypes for biological-control programs, compared across generations to a regularline laboratory-reared for more than 60 generations. The flight capacity of the isoline was best at 25-30 °C and relative humidity 70-90%.
Assuntos
Agentes de Controle Biológico , Vespas , Animais , Óvulo , Spodoptera/genéticaRESUMO
The intraclass correlation is commonly used with clustered data. It is often estimated based on fitting a model to hierarchical data and it leads, in turn, to several concepts such as reliability, heritability, inter-rater agreement, etc. For data where linear models can be used, such measures can be defined as ratios of variance components. Matters are more difficult for non-Gaussian outcomes. The focus here is on count and time-to-event outcomes where so-called combined models are used, extending generalized linear mixed models, to describe the data. These models combine normal and gamma random effects to allow for both correlation due to data hierarchies as well as for overdispersion. Furthermore, because the models admit closed-form expressions for the means, variances, higher moments, and even the joint marginal distribution, it is demonstrated that closed forms of intraclass correlations exist. The proposed methodology is illustrated using data from agricultural and livestock studies.
Assuntos
Biometria/métodos , Modelos Lineares , Agricultura/estatística & dados numéricos , Animais , Gado , Reprodutibilidade dos Testes , Estatística como AssuntoRESUMO
The objective of the present study was to determine whether blow flies (Diptera: Calliphoridae) are able to identify larvae of an intraguild predator species in the substrate and avoid laying eggs there. Blow flies oviposited in traps with different treatments: substrate only and substrate with larvae of Chrysomya albiceps (Wiedemann, 1819), Chrysomya megacephala (Fabricius, 1794), or Chrysomya putoria (Wiedemann, 1830). Ch. megacephala, Ch. putoria, and Lucilia eximia (Wiedemann, 1819) avoided laying eggs in the trap containing Ch. albiceps larvae. Cochliomyia macellaria (Fabricius, 1775) did not oviposit differently in each substrate but had overall low abundance. The prevalence of species on corpses may be influenced by the ability of the species to detect the presence of other species, mainly predators. In this sense, intraguild predation may result in misinterpretations of a crime scene and should be considered when assessing the minimum postmortem interval.
Assuntos
Dípteros/fisiologia , Oviposição , Comportamento Predatório , Animais , Feminino , LarvaRESUMO
A common practice in poultry science is to compare new treatments with a control or between treatments tested in planned experiments. The overall F-test from an ANOVA of the data allows the researcher to reject or not reject the null hypothesis. However, the correct conclusion from such analysis depends on sufficient replicates being included in the experiment. On the other hand, restrictions are imposed to reduce the number of birds used in experiments for welfare reasons and to save scarce resources. We review the basic concepts needed to determine the number of replicates before conducting an experiment. We use these concepts to assess the results of several real experiments and to show what might be done in future experiments. We describe how to do the computations in R software.